package com.dong.common.utils.excel;

import org.apache.poi.hssf.util.CellReference;
import org.apache.poi.ss.usermodel.DateUtil;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import java.io.*;
import java.util.Calendar;
import java.util.Enumeration;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
import java.util.zip.ZipOutputStream;

/**
 * Excel超大数据写入，抽象excel2007读入器，先构建.xlsx一张模板，改写模板中的sheet.xml,
 * 使用这种方法 写入.xlsx文件，不需要太大的内存
 */
public abstract class ExcelWriter {

    private SpreadsheetWriter sw;

    /**
     * 写入电子表格的主要流程
     *
     * @param fileName
     * @throws Exception
     */
    @SuppressWarnings("resource")
    public void process(String fileName) throws Exception {

        // 建立工作簿和电子表格对象
        XSSFWorkbook wb = new XSSFWorkbook();
        XSSFSheet sheet = wb.createSheet("sheet1");

        // 持有电子表格数据的xml文件名 例如 /xl/worksheets/sheet1.xml
        String sheetRef = sheet.getPackagePart().getPartName().getName();

        // 保存模板
        FileOutputStream os = new FileOutputStream("template.xlsx");
        wb.write(os);
        os.close();

        // 生成xml文件
        File tmp = File.createTempFile("sheet", ".xml");
        Writer fw = new FileWriter(tmp);
        sw = new SpreadsheetWriter(fw);
        generate();
        fw.close();

        // 使用产生的数据替换模板
        File templateFile = new File("template.xlsx");
        FileOutputStream out = new FileOutputStream(fileName);
        substitute(templateFile, tmp, sheetRef.substring(1), out);
        out.close();
        // 删除文件之前调用一下垃圾回收器，否则无法删除模板文件
        System.gc();
        // 删除临时模板文件
        if (templateFile.isFile() && templateFile.exists()) {
            templateFile.delete();
        }
    }

    /**
     * 类使用者应该使用此方法进行写操作
     *
     * @throws Exception
     */
    public abstract void generate() throws Exception;

    public void beginSheet() throws IOException {
        sw.beginSheet();
    }

    public void insertRow(int rowNum) throws IOException {
        sw.insertRow(rowNum);
    }

    public void createCell(int columnIndex, String value) throws IOException {
        sw.createCell(columnIndex, value, -1);
    }

    public void createCell(int columnIndex, double value) throws IOException {
        sw.createCell(columnIndex, value, -1);
    }

    public void endRow() throws IOException {
        sw.endRow();
    }

    public void endSheet() throws IOException {
        sw.endSheet();
    }

    /**
     * @param zipfile the template file
     * @param tmpfile the XML file with the sheet data
     * @param entry   the name of the sheet entry to substitute, e.g. xl/worksheets/sheet1.xml
     * @param out     the stream to write the result to
     */
    private static void substitute(File zipfile, File tmpfile, String entry,
                                   OutputStream out) throws IOException {
        ZipFile zip = null;
        ZipOutputStream zos = null;
        InputStream is = null;
        try {
            zip = new ZipFile(zipfile);
            zos = new ZipOutputStream(out);
            @SuppressWarnings("unchecked")
            Enumeration<ZipEntry> en = (Enumeration<ZipEntry>) zip.entries();
            while (en.hasMoreElements()) {
                ZipEntry ze = en.nextElement();
                if (!ze.getName().equals(entry)) {
                    zos.putNextEntry(new ZipEntry(ze.getName()));
                    InputStream is2 = null;
                    try {
                        is2 = zip.getInputStream(ze);
                        copyStream(is2, zos);
                    } finally {
                        if (is2 != null) {
                            is2.close();
                        }
                    }
                }
            }
            zos.putNextEntry(new ZipEntry(entry));
            is = new FileInputStream(tmpfile);
            copyStream(is, zos);
        } finally {
            if (is != null) {
                is.close();
            }
            if (zos != null) {
                zos.close();
            }
            if (zip != null) {
                zip.close();
            }
        }
    }

    private static void copyStream(InputStream in, OutputStream out)
            throws IOException {
        byte[] chunk = new byte[1024];
        int count;
        while ((count = in.read(chunk)) >= 0) {
            out.write(chunk, 0, count);
        }
    }

    /**
     * 在写入器中写入电子表格
     */
    public static class SpreadsheetWriter {
        private final Writer _out;
        private int _rownum;
        private static String LINE_SEPARATOR = System
                .getProperty("line.separator");

        public SpreadsheetWriter(Writer out) {
            _out = out;
        }

        public void beginSheet() throws IOException {
            _out.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>"
                    + "<worksheet xmlns=\"http://schemas.openxmlformats.org/spreadsheetml/2006/main\">");
            _out.write("<sheetData>" + LINE_SEPARATOR);
        }

        public void endSheet() throws IOException {
            _out.write("</sheetData>");
            _out.write("</worksheet>");
        }

        /**
         * 插入新行
         *
         * @param rownum 以0开始
         */
        public void insertRow(int rownum) throws IOException {
            _out.write("<row r=\"" + (rownum + 1) + "\">" + LINE_SEPARATOR);
            this._rownum = rownum;
        }

        /**
         * 插入行结束标志
         */
        public void endRow() throws IOException {
            _out.write("</row>" + LINE_SEPARATOR);
        }

        /**
         * 插入新列
         *
         * @param columnIndex
         * @param value
         * @param styleIndex
         * @throws IOException
         */
        public void createCell(int columnIndex, String value, int styleIndex)
                throws IOException {
            String ref = new CellReference(_rownum, columnIndex)
                    .formatAsString();
            _out.write("<c r=\"" + ref + "\" t=\"inlineStr\"");
            if (styleIndex != -1) {
                _out.write(" s=\"" + styleIndex + "\"");
            }
            _out.write(">");
            _out.write("<is><t>" + encoderXML(value) + "</t></is>");
            _out.write("</c>");
        }

        public void createCell(int columnIndex, String value)
                throws IOException {
            createCell(columnIndex, value, -1);
        }

        public void createCell(int columnIndex, double value, int styleIndex)
                throws IOException {
            String ref = new CellReference(_rownum, columnIndex)
                    .formatAsString();
            _out.write("<c r=\"" + ref + "\" t=\"n\"");
            if (styleIndex != -1) {
                _out.write(" s=\"" + styleIndex + "\"");
            }
            _out.write(">");
            _out.write("<v>" + value + "</v>");
            _out.write("</c>");
        }

        public void createCell(int columnIndex, double value)
                throws IOException {
            createCell(columnIndex, value, -1);
        }

        public void createCell(int columnIndex, Calendar value, int styleIndex)
                throws IOException {
            createCell(columnIndex, DateUtil.getExcelDate(value, false),
                    styleIndex);
        }
    }

    // XML Encode
    private static final String[] xmlCode = new String[256];

    static {
        // Special characters
        xmlCode['\''] = "'";
        xmlCode['\"'] = "\""; // double quote
        xmlCode['&'] = "&"; // ampersand
        xmlCode['<'] = "<"; // lower than
        xmlCode['>'] = ">"; // greater than
    }

    /**
     * <p>
     * Encode the given text into xml.
     * </p>
     *
     * @param string the text to encode
     * @return the encoded string
     */
    public static String encoderXML(String string) {
        if (string == null) {
            return "";
        }
        int n = string.length();
        char character;
        String xmlchar;
        StringBuffer buffer = new StringBuffer();
        // loop over all the characters of the String.
        for (int i = 0; i < n; i++) {
            character = string.charAt(i);
            // the xmlcode of these characters are added to a StringBuffer
            // one by one
            try {
                xmlchar = xmlCode[character];
                if (xmlchar == null) {
                    buffer.append(character);
                } else {
                    buffer.append(xmlCode[character]);
                }
            } catch (ArrayIndexOutOfBoundsException aioobe) {
                buffer.append(character);
            }
        }
        return buffer.toString();
    }

//	/**
//	 * 测试方法
//	 */
//	public static void main(String[] args) throws Exception {
//
//		String file = "E:/测试导出数据.xlsx";
//		
//		ExcelWriter writer = new ExcelWriter() {
//			@Override
//			public void generate() throws Exception {
//				
//				// 电子表格开始
//				this.beginSheet();
//				
//				for (int rownum = 0; rownum < 100; rownum++) {
//					// 插入新行
//					this.insertRow(rownum);
//					
//					// 建立新单元格,索引值从0开始,表示第一列
//					this.createCell(0, "第 " + rownum + " 行");
//					this.createCell(1, 34343.123456789);
//					this.createCell(2, "23.67%");
//					this.createCell(3, "12:12:23");
//					this.createCell(4, "2014-10-11 12:12:23");
//					this.createCell(5, "true");
//					this.createCell(6, "false");
//
//					// 结束行
//					this.endRow();
//				}
//				
//				// 电子表格结束
//				this.endSheet();
//			}
//		};
//		writer.process(file);
//	}

}
